Spark plug



March 15, 1938. s. A. KOSTYK ET AL SPARK PLUG Filed Aug. 31, 1956 3mm $720677 flOSTg/O,

UNITED STATES SPARK PLUG Steven A. Kostyk and Frank H. Schofield, Cleveland, Ohio Application August 31, 1936, Serial No. 98,762

1 Claim.

This invention relates to improvements in spark plugs for internal combustion engines, of that type wherein both electrodes of the spark plug are encased or embedded within the porcelain or insulator core of the plug, thereby avoiding the necessity of attaching the ground electrode to the metal body or casing of the spark plug and permitting ready replacement of an old cracked core by a new one so as to maintain a satisfactory plug in which the metal body or casing and the clamping gland are continuously used.

An object of the present invention is to provide a simple and inexpensive spark plug of the above type wherein means is provided to insure a good electrical connection between the ground electrode and the metal body or casing of the plug.

Another object of the present invention is to provide the electrodes with sparking terminals so formed and related as to insure quick drainage of oil therefrom for minimizing carbon deposits thereon, and to lead the drained oil away from the opposed portions of the terminals between which the sparks pass so that the oil will not be likely to cause a short circuit and interruption of the sparks.

The present invention consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawing and claimed.

In the drawing:

Figure 1 is an elevational view of a spark plug constructed in accordance with the present invention.

Figure 2 is a central longitudinal section thereof and Figure 3 is an elevational view of the porcelain or insulator core.

Referring in detail to the drawing, the present spark plug consists of the usual metal body or casing 5 having a reduced externally threaded lower end portion 6 adapted to be threaded into the usual spark plug opening of the engine, the usual internal shoulder I being afiorded within the intermediate portion of the body or casing 5 at the juncture of the larger upper portion of said body 5 with the reduced lower portion thereof. Also, the upper end of the body 5 is internally threaded in the usual way for reception of the usual threaded clamping gland or collar 8.

The present plug also includes an ordinary porcelain or insulator core 9 having an enlarged intermediate portion providing upper and lower external annular shoulders Ill and I I respectively engageable by the lower beveled end of the gland or collar 8 and the internal shoulder I of the body 5. The usual compressible Washers I2 and I3 are provided between the upper shoulder I I] and the lower end of gland or collar 8 and between the lower shoulder II and the internal shoulder I of body 5, respectively, for allowing limited expansion of the metal part surrounding the core 9 and for preventing leakage of gas between the core 9 and the parts 5 and 8.

Both electrodes I4 and I5 are encased or embedded in the porcelain or insulator core 9 of the plug, and the electrode I4 extends the full length of the porcelain or core and is engaged at its upper end with the usual thumb nut I6 for facilitating connection of the usual feed wire thereto. The upper end of electrode I5, which isthe shorter one, extends to and terminates slightly above the surface of the upper shoulder III of the core 9, such upper terminal of electrode I5 being in the form of a slightly projecting sharpened point or edge I'I. Thus, when the clamping gland or collar 8 is screwed in place the sharpened projecting end of electrode I5 is caused to bite into or penetrate the adjacent compressible washer I2 so as to make good electrical contact therewith, the grounding circuit of the electrode I5 being completed through the washer I2 and gland or collar 8 to the body 5.

The lower ends of the electrodes I4 and I5 project below the lower end of core 9 and are bent to provide downwardly converging inclined sparking terminals I8 and I9, from which oil may readily and quickly drain so as to minimize the deposit of carbon thereon. In order to lead the drained oil away from the opposed portions of the terminals I8 and I9 between which the sparks pass, so as to avoid short circuiting of the terminals at these opposed portions with consequent interference with the occurrence of the sparks, one of the electrodes is provided on its sparking terminal with a short axial extension 20. As shown, this extension 20 is provided onthe terminal I9 of the ground electrode I5.

,It will be apparent that a spark plug constructed in accordance with the present invention will be economical to produce. Also, should the electrodes become shorted due to cracking of the core 9, said core may be readily removed and replaced by a new one ,so as to afford an' efiicient spark plug making continuous use of the body 5 and gland or collar 8.

What we claim as new is:

A spark plug of the character described comprising insulated feed and ground electrodes provided with inclined and downwardly converging sparking terminals for facilitating drainage of oil therefrom, one of said terminals having a short axial extension to lead the drained oil away from the opposed portions of said terminals between which the sparks are adapted to pass so as to minimize shorting of the electrodes between such portions of the terminals.

STEVEN A. KOSTYK. FRANK H. SCHOFIELD. 

